Parton densities from LHC vector boson production at small and large transverse momenta

Klasen, M.; Brandt, Matthias

doi:10.1103/physrevd.88.054002

Cited by 14 publications

(14 citation statements)

References 75 publications

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“…In particular, very little is known about the gluon PDF in nuclei, which is, however, important to understand nuclear shadowing [8] and its possible relation to diffraction [9], saturation [10], and the initial condition for the creation of the quark-gluon plasma in heavy-ion collisions [11]. The situation could be somewhat improved by including pion production data from BNL RHIC [12], albeit at the cost of introducing a fragmentation function uncertainty, and recently also with the first electroweak boson [13] and in particular dijet [14] data from pPb collisions at the CERN LHC [15]. In addition, a recent reweighting study has shown also that forward heavy-quark and quarkonium production data from the CERN LHC have the potential to better constrain future analyses [16].…”

Section: Introductionmentioning

confidence: 99%

Nuclear parton density functions from dijet photoproduction at the EIC

Klasen

Kovařı́k

2018

Phys. Rev. D

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We study the potential of dijet photoproduction measurements at a future electron-ion collider (EIC) to better constrain our present knowledge of the nuclear parton distribution functions. Based on theoretical calculations at next-to-leading order and approximate next-to-next-to-leading order of perturbative QCD, we establish the kinematic reaches for three different EIC designs, the size of the parton density function modifications for four different light and heavy nuclei from He-4 over C-12 and Fe-56 to Pb-208 with respect to the free proton, and the improvement of EIC measurements with respect to current determinations from deep-inelastic scattering and Drell-Yan data alone as well as when also considering data from existing hadron colliders.

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Section: Introductionmentioning

confidence: 99%

Nuclear parton density functions from dijet photoproduction at the EIC

Klasen

Kovařı́k

2018

Phys. Rev. D

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“…Indeed, this process dominates for inclusive Z production within a rapidity range of |y| < 2.1. However, already for Z transverse momenta around 25 GeV quark-gluon scattering qg → Zq is of similar size, and around p T = 100 GeV the latter process constitutes 80% of the total cross section [157]. For Z-boson transverse momenta of 180 GeV, parton-momentum fractions x 1/2 = (M/ √ s) exp(±y) of about x = 0.05 are probed.…”

Section: Differential Vector-boson Cross Sectionsmentioning

confidence: 97%

Studies of Quantum Chromodynamics at the LHC

Carli¹,

Rabbertz²,

Schumann³

2015

The Large Hadron Collider

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Abstract. A successful description of hadron-hadron collision data demands a profound understanding of quantum chromodynamics. Inevitably, the complexity of strong-interaction phenomena requires the use of a large variety of theoretical techniques-from perturbative cross-section calculations up to the modelling of exclusive hadronic final states. Together with the unprecedented precision of the data provided by the experiments in the first running period of the LHC, a solid foundation of hadron-hadron collision physics at the TeV scale could be established that allowed the discovery of the Higgs boson and that is vital for estimating the background in searches for new phenomena. This chapter on studies of quantum chromodynamics at the LHC is part of a recent book on the results of LHC Run 1 [1] and presents the advances in theoretical methods side-by-side with related key measurements in an integrated approach.

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“…At the low p T (Z) region, p T (Z) < ∼ 20 GeV, the sub-process with initial state qq has significant contribution to the total cross section, while in the high p T (Z) region, p T (Z) > ∼ M Z /2, the sub-process gq becomes dominant (∼ 70 -80%). These relative sub-process contributions are also valid at the NLO accuracy [12,22,23]. Therefore, the inclusive Z boson production cross section is one of the potential measurement to probe the gluon density inside the proton at the LHC [24].…”

Section: Introduction 2 Inclusive Z Production At Lhcmentioning

confidence: 99%

QCD analysis of the CMS inclusive differentialZproduction data ats=8 TeV

2016

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The parton distribution functions (PDFs) of the proton are one of the essential ingredients to describe physics processes at hadron colliders. The Z boson production data at the LHC have a potential to constrain PDFs, especially the gluon distribution. In this study the CMS measurement of the inclusive double differential Z boson production cross section in terms of transverse momentum and rapidity are compared to the next-to-leading order theory predictions at the center of mass energy, √ s=8 TeV with an integrated luminosity of 19.71 f b −1 . In addition, the sensitivity of this measurement to PDFs is studied within the framework of the HERAFitter. A moderate improvement to the gluon distribution is observed at the Bjorken x ≈ 0.1 region. However, in order to obtain further improvement to the gluon distribution in the global fits, the higher-order theory calculations accessible via fast techniques are necessary.The precision measurements of the Standard Model (SM) of particle physics are one of the top priority programmes at the LHC. The accurate theory predictions are necessary in order to completely exploit the potential of the SM measurements. Importantly, in the hadron colliders parton distribution functions (PDFs) are one of the necessary ingredients for theory predictions. Naively, the PDF f i (x, Q 2 ) represent the probability of finding a parton of flavour i (where i: g(gluons),q (quarks); q=u,d,c,s..) inside a proton carrying a fraction x of the momentum of the proton at the scale Q, called the factorization scale related with the hard scale of the involved physical process. The PDFs cannot be derived from the first principles of Quantum Chromodynamics (QCD) [1] and have to be constrained experimentally. The PDFs are constrained primarily by the Deep Inelastic Scattering (DIS) data. Additional constraints come from the Fixed-target, Tevatron and LHC measurements [for more details, see for example, the reviews in Ref. [2,3] and references therein].Currently, various published SM measurements at the LHC with the center of mass energies 7 and 8 TeV are already used in the global PDF fits [4][5][6][7]. Besides these global PDF fitting efforts, the sensitivity of the particular LHC measurement to PDFs are also studied. For example, PDFs are constrained using the measurement of the W and Z production to strange quark distribution in ATLAS [8], the CMS W charge asymmetry [9] and W in association with the charm quark measurements at 7 TeV [10], W boson production in association with a single charm quark in ATLAS [11], the inclusive jet cross sections from the LHC [12][13][14][15], top quark pair production [16,17] etc. In this current analysis, the impact to the PDFs of the CMS production cross section measurement of the Z boson decaying to a pair of muons [18,19] is studied. This measurement is performed in various bins of transverse momentum (p T (Z)) and rapidity (Y (Z)) of the Z boson. The QCD analysis is performed at the Next-to-Leading order(NLO) in the framework of the HERAFitter [20]. Along with the C...

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Parton densities from LHC vector boson production at small and large transverse momenta

Cited by 14 publications

References 75 publications

Nuclear parton density functions from dijet photoproduction at the EIC

Nuclear parton density functions from dijet photoproduction at the EIC

Studies of Quantum Chromodynamics at the LHC

QCD analysis of the CMS inclusive differentialZproduction data ats=8 TeV

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